1. Field of the Invention
The present invention relates to a method for producing carbon micro- and nano-coils using sulfur hexafluoride gas, and more particularly to a method for producing carbon micro- and nano-coils using sulfur hexafluoride gas, wherein the carbon micro- and nano-coils are synthesized and grown on a ceramic substrate and sulfur hexafluoride is introduced during the synthesis of the carbon coils to control the geometry of the carbon coils.
2. Description of the Prior Art
It is known that carbon microcoils (hereinafter referred to as CMCs) can be synthesized with micrometer or nanometer dimensions and was found by Davis et al. in 1953 (An unusual form of carbon, Nature, 171 (1953) 756). Many new materials are currently used in industrial applications, and among them, carbon fibers are widely used as new reinforcing materials. Carbon microcoils are defined as amorphous carbon fibers coiled with a pitch of 1/1000 mm (micrometer) and are new carbon materials which are expected to be widely used in electromagnetic absorbers, microwave heating materials, tactile proximity sensors, micro-antennas, biological activators and like.
CMCs can be synthesized by thermally decomposing acetylene containing a trace amount of sulfur impurities in the presence of a catalyst such as Ni, but are very difficult to grow compared to carbon nanotubes. Thus, if a catalyst, reaction conditions and system conditions are not optimized, only fine carbon powders or straight carbon fibers will be obtained. As the raw material, acetylene is mainly used, and methane, propane, benzene or the like may also be used, but in this case, the yield and stability of the resulting coils will be reduced. One of the special features of CMCs is excellent elasticity. Coils having a large diameter and coils having a small fiber diameter show very high elasticity in that the original length of the coils can be stretched by about 15 times. Micro- or nano-sized CMCs have a high degree of new functions which cannot be obtained in existing materials, and thus they are expected to be suitably used in applications in which existing materials cannot be used.